Quantitative Analysis of Retinal Microvascular Changes after Conbercept Therapy in Branch Retinal Vein Occlusion Using Optical Coherence Tomography Angiography

Soul: An OCTA dataset based on Human Machine Collaborative Annotation Framework

Branch retinal vein occlusion (BRVO) is the most prevalent retinal vascular disease that constitutes a threat to vision due to increased venous pressure caused by venous effluent in the space, leading to impaired visual function. Optical Coherence Tomography Angiography (OCTA) is an innovative non-invasive technique that offers high-resolution three-dimensional structures of retinal blood vessels. Most publicly available datasets are collected from single visits with different patients, encompassing various eye diseases for distinct tasks and areas. Moreover, due to the intricate nature of eye structure, professional labeling not only relies on the expertise of doctors but also demands considerable time and effort. Therefore, we have developed a BRVO-focused dataset named Soul (Source of ocular vascular) and propose a human machine collaborative annotation framework (HMCAF) using scrambled retinal blood vessels data. Soul is categorized into 6 subsets based on injection frequency and follow-up duration. The dataset comprises original images, corresponding blood vessel labels, and clinical text information sheets which can be effectively utilized when combined with machine learning.

Central and Peripheral Changes in Retinal Vein Occlusion and Fellow Eyes in Ultra-Widefield Optical Coherence Tomography Angiography

Purpose

To explore the central and peripheral retinal and choroidal changes in retinal vein occlusion (RVO) and fellow eyes using ultra-widefield swept-source optical coherence tomography angiography (UWF-SS-OCTA).

Methods

Fifteen ischemic central RVO (CRVO), 15 branch RVO (BRVO), and 15 age-matched healthy controls were prospectively recruited. Retinal and choroidal parameters, including retinal vessel flow density (VFD) and vessel linear density (VLD), choroidal vascularity volume (CVV), choroidal vascularity index (CVI), and VFD in the large and medium choroidal vessels (LMCV-VFD), were measured in the central and peripheral regions of the 24 × 20-mm UWF-SS-OCTA images.

Results

Ischemic CRVO and BRVO eyes showed increased foveal avascular zone area, perimeter, and acircularity index (AI) compared to their fellow eyes and healthy control eyes, and RVO fellow eyes also had larger AI values than controls (P < 0.05). For ischemic CRVO and BRVO eyes versus control eyes, VFD, VLD, CVV, CVI, and LMCV-VFD decreased, but retinal thickness and volume in the superficial capillary plexus, deep capillary plexus, and whole retina increased (P < 0.05). Moreover, RVO fellow eyes also showed significantly decreased retinal VFD, LMCV-VFD, and CVI, as well as increased retinal thickness and volume, compared with control eyes (P < 0.05). Alterations were not consistent throughout the retina, as they involved only the peripheral or central regions in some cases.

Conclusions

The affected and unaffected fellow eyes of RVO patients both demonstrated central and/or peripheral structural and vascular alterations in the retina and choroid. Because UWF-SS-OCTA enables visualization and evaluation of the vasculature outside the posterior pole, it presents a promising approach to more fully characterize vascular alterations in RVO.

Effect of Conbercept on Corneal Neovascularization in a Rabbit Model

OBJECTIVE

To study the efficacy of Conbercept for the treatment of corneal neovascularization (NV) in a rabbit model.

METHODS

NV was induced by placing sutures. Eight rabbits were used as a control. The other 136 rabbits were randomly divided into two equal groups, and 68 rabbits in each group were divided into four subgroups and given different treatments. Time-course photographs, histological examination, and enzyme-linked immunoassay ELISA analysis for vascular endothelial growth factor were performed at weeks 1, 2, and 3 after injection placement.

RESULTS

At weeks 1, 2, and 3 after injection placement, there was less expression of corneal NV and VEGF in the conbercept-treated groups than in the saline-treated control groups and less corneal NV and VEGF were expressed in the early treatment group than in the late treatment group. At weeks 2 and 3 after injection, there were fewer corneal NV (length and area) in the early intrastromal injection group with conbercept than in the early subconjunctival injection group with conbercept and a smaller diameter of corneal NV than in the late intrastromal injection group treated with conbercept. Histological examination showed a smaller diameter of corneal NV in all eyes in conbercept-treated groups 1 w after injection than before injection. Treatment with subconjunctival injection with conbercept led to a larger diameter at weeks 2 and 3 than at week 1.

CONCLUSIONS

Subconjunctival and intrastromal administrations of conbercept effectively inhibit corneal NV in rabbits, and the latter has the better effect. The effect is the best in the group with cornea intrastromal injection of conbercept 1 w after suture. Early administration of conbercept may successfully inhibit corneal NV in an animal model.

Central macular OCTA parameters in glaucoma

BACKGROUND/AIMS

To investigate the relationship between the foveal avascular zone (FAZ) parameters assessed by optical coherence tomography angiography (OCTA) and central visual field parameters in glaucoma and healthy subjects.

METHODS

One hundred and eighty-eight subjects (248 eyes), including 24 healthy (38 eyes), 37 glaucoma suspect (42 eyes, and 127 primary open angle glaucoma (POAG) patients (168 eyes), underwent imaging using OCTA and standard automated perimetry using the 24-2 and 10-2 Swedish Interactive Thresholding Algorithm. OCTA-based and OCT-based FAZ parameters (superficial FAZ area, FAZ circumference), foveal vessel density (FD300) and foveal thickness were measured. The correlation between FAZ parameters and visual field parameters was assessed using linear mixed model.

RESULTS

Axial length adjusted-FAZ area was not different among the three groups (mean (95% CI)): in healthy 0.31 (0.27 to 0.36) mm², glaucoma suspect 0.29 (0.26 to 0.31) mm² and POAG eyes 0.28 (0.27 to 0.30) mm² (p=0.578). FD300 was lower in glaucoma suspect 49.1% (47.9% to 50.4%) and POAG eyes 48.7% (48.1% to 49.4%) than healthy eyes 50.5% (49.3% to 51.7%) though the difference was not statistically significant (p=0.071). Lower FD300 was associated with worse 24-2 and 10-2 visual field mean deviation and foveal threshold in multivariable linear mixed models (all p<0.05). In addition, a smaller FAZ area was associated with lower intraocular pressure (IOP) (p=0.026).

CONCLUSIONS

The FD300, but not the FAZ area was correlated with 10° central visual field mean deviation and foveal threshold in healthy, glaucoma suspect and POAG eyes. In contrast, a smaller FAZ area was associated with lower IOP.

Serial choriocapillaris flow changes in eyes with branched retinal vascular obstruction (BRVO)

PURPOSE

To evaluate the choriocapillaris (CC) flow changes in branched retinal vascular obstruction (BRVO) on optical coherence tomography angiography (OCTA).

METHODS

Retrospective analysis of 29 patients with unilateral BRVO (58 eyes, including unaffected fellow eyes for controls). 4.5 x 4.5 mm macular scans were divided into 4 quadrants. Serial analyses were conducted on CC flow voids of the opposite quadrant to the active occluded area in BRVO eyes. Each of the quadrants were also compared to the occluded quadrant of resolved eyes and the contralateral quadrant of fellow eyes by matched data analysis. A regression analysis was performed on the several parameters (Choroidal thickness; CT, Choroidal vascularity index; CVI, Central macular thickness; CMT, The number of intravitreal injections) and CC flow voids.

RESULTS

The CC flow void increased sequentially: The uninvolved quadrant of acute BRVO-affected eyes, that of resolved eyes after 3-month/1-year, the contralateral quadrant of fellow eye, the involved (occluded) quadrant of resolved eyes. There were significant correlations between initial CMT, the number of injections and the CC flow void of uninvolved quadrants (P = 0.025, 0.031, respectively), and between the involved (occluded) quadrants and fellow CT (P = 0.029).

CONCLUSION

CC flow void of uninvolved macular areas decreased significantly in eyes with acute BRVO, suggesting that CC changes were limited to the blocked area and a compensatory mechanism would work in surrounding areas.

Structural and Visual Changes in Branch Retinal Vein Occlusion Patients with Retinal Atrophy

Background

To study the changes of retinal vascular density (VD), retinal thickness (RT), and their correlations with visual acuity (VA) in branch retinal vein occlusion (BRVO) patients with retinal atrophy after resolution of macular oedema (MO).

Methods

This is a retrospective study consisting of 46 patients diagnosed with BRVO at Beijing Hospital from 2015 to 2019. Patients' 46 affected eyes and 39 fellow eyes were included. The affected eyes were further divided into the atrophy group and the nonatrophy group. Optical coherence tomography (OCT) and optical coherence tomography angiography (OCTA) images obtained when MO completely resolved after treatment with ranibizumab were analyzed. We quantitatively measured foveal avascular zone (FAZ) parameters, the disruption extent of ellipsoid zone (EZ), RT, and VD of superficial vascular complex (SVC), and deep vascular complex (DVC) in central fovea and the minimal-VD quadrant. Paired t-tests, independent t-tests, Mann–Whitney U tests, Wilcoxon tests, Pearson correlation analyses, Spearman correlation analyses, and single and multiple linear regression models were adopted.

Results

Compared with nonatrophy eyes, the minimal-VD quadrantal (quadrantal for short) SVC-VD (25.76 ± 4.57% versus 36.21 ± 6.47%, P < 0.001) and quadrantal DVC-VD (27.72 (17.23) % versus 38.95 (11.05) %, P = 0.001) of atrophy eyes decreased significantly. Quadrantal SVC-VD and quadrantal DVC-VD were strongly correlated with quadrantal full RT (r = 0.763 and 0.698, both P < 0.001). The disruption length of EZ was significantly correlated with quadrantal full RT (r = −0.406, P = 0.005) and quadrantal SVC-VD (r = −0.298, P = 0.044). In multiple linear regression analysis, the disruption length of EZ and VA before treatment and age showed significant correlations with VA with complete resolution of MO (P = 0.020,  0.033,  and 0.002).

Conclusions

The retinal VD on the affected area correlates well with the corresponding full RT when BRVO-MO completely resolves, suggesting that VD may predict the final RT. Severe decrease in VD may result in retinal atrophy, which may cause VA loss indirectly with the intermediate influencing factor of EZ defects.

Potential Prognostic Indicators for Patients With Retinal Vein Occlusion

The second most prevalent cause of retinal vascular disease is retinal vein occlusion (RVO). RVO raises intravascular pressure in the capillary and veins, triggering vessel barrier collapse and subsequent leaking of blood or plasma components into the tissue (edema). Macular edema (ME) is a major complication of RVO that results in significant visual impairment. Laser therapy, intravitreal steroid injections, and vascular endothelial growth factor (VEGF) inhibitors are the major therapeutic techniques. Different therapies reduce ME of RVO and improve visual activity. However, some people have no impact on the resolution of ME, while others have a poor visual prognosis despite full ME cure. There are many investigators who studied the relationship between indicators of various instruments with visual activity. However, a summary of those findings is currently lacking. Therefore, we will focus on the predictive factors of different studies associated with positive visual activity outcomes, which would be very useful and important to help address both treatment expectations and methods for patients with RVO.

Research progress of UWFFA and OCTA in retinal vein occlusion: A review

Retinal vein occlusion (RVO) is a retinal vascular disease that severely impairs the visual function of patients. Observing the changes of retinal blood vessels before and after treatment is of great significance for the prognostic evaluation of RVO. The rapid development and widespread use of fundus imaging technique, especially ultra-wide-angle fundus fluorescein angiography (UWFFA) and optical coherence tomography angiography (OCTA) have made our observation of the retinal blood vessels of RVO more comprehensive and meticulous. In this paper, we reviewed the latest research progress of UWFFA and OCTA in RVO.

Vascular Abnormalities in Peripapillary and Macular Regions of Behcet's Uveitis Patients Evaluated by Optical Coherence Tomography Angiography

Purpose: To investigate the involvement of peripapillary zone vascular abnormalities in Behcet's uveitis (BU) and associated visual dysfunction. We evaluated the retinal and choroidal microvascular features in both macular and peripapillary areas of BU patients to identify vascular abnormalities contributing to reduced best-corrected visual acuity (BCVA) using optical coherence tomography angiography (OCTA). Methods: A prospective, observational study was conducted in 24 eyes of 13 patients with BU and 24 eyes of 15 healthy participants as controls. They received a standard eye examination and were recorded by OCTA measurements of macular and peripapillary areas. The vascular densities of superficial capillary plexus (SCP) and deep capillary plexus (DCP), choroidal flow area, radial peripapillary capillary network (RPCN) density, foveal avascular zone (FAZ) area and perimeter, full retinal thickness (FRT), and peripapillary retinal nerve fiber layer thickness (pRNFLT) were measured.Correlations among microvascular, structural, and functional changes were assessed. Results: Our findings uncovered that the vascular density was significantly reduced in the peripapillary zone of BU eyes compared to healthy eyes, especially in the inferior subfield of the RPCN. The vascular densities of SCP and DCP quadrants within the macular zone had no significant difference between BU and control groups except for DCP density of the nasal parafoveal quadrant. Both FAZ area and perimeter were greater but without statistical significance in the BU group. Compared to healthy eyes, the choriocapillaris flow area was smaller while the FRT and pRNFLT were greater in the BU group. Notably, there was a significant correlation between the reduction in RPCN vascular density and decreased BCVA in BU patients. Conclusion: Based on OCTA, vascular changes associated with BU are more prominent in the peripapillary zone than those in the macular zone. The vascular density of the RPCN could serve as a sensitive indicator to monitoring BU pathogenic progression and treatment response using a non-invasively method of OCTA.

Changes in Macular Microvascular Structure in Macular Edema Secondary to Branch Retinal Vein Occlusion Treated with Antivascular Endothelial Growth Factor for One Year

Purpose

To observe the changes in macular microvascular structure and the correlation between anatomy and visual function in patients with macular edema secondary to branch retinal vein occlusion (BRVO) treated with antivascular endothelial growth factor for one year.

Methods

This prospective study enrolled 39 patients (one eye per patient) who received intravitreal injections of ranibizumab for macular edema secondary to BRVO. All patients received a minimum of 3 initial monthly ranibizumab injections and criteria-driven pro re nata (PRN) dosing thereafter for visual acuity (VA) and central retinal thickness (CRT) stabilization. The follow-up period of this study was one year. The vascular density (VD) of the superficial retinal capillary plexus (SCP) and deep retinal capillary plexus (DCP), the foveal avascular zone (FAZ) area, the FAZ perimeter, the VD within a 300 μm wide ring surrounding the FAZ (FD-300), and the acircularity index (AI) were measured automatically by optical coherence tomography angiography (OCTA) at baseline, month 6, and month 12.

Results

Compared with those before treatment, the VD of the SCP significantly decreased 6 months after treatment (P < 0.05), while the area and perimeter of the FAZ increased significantly (P < 0.01). After 12 months of treatment, the area and perimeter of the FAZ increased significantly (P < 0.01). There was no significant difference in any parameters between 12 months and 6 months after treatment (P > 0.05). The change in BCVA was negatively correlated with the VD of the SCP at 12 months (P=0.0447, r = -0.3233). There was a relationship between the DBP and AI, and CRT was related to VD of DCP at baseline (P=0.028,  0.0209; r = 0.383, -0.384). The PERIM and AI at 12 months were significantly associated with the recurrence of macular edema, and the changes in vascular density in the SCP and PERIM were significantly associated with the number of injections within 12 months (P < 0.05).

Conclusions

One year after ranibizumab treatment, the area and perimeter of the FAZ were enlarged, while the VD of the SCP and DCP remained stable, which indicated that ranibizumab treatment did not improve macular blood supply and macular ischemia in BRVO patients.

Retinal Vascularization Analysis on Optical Coherence Tomography Angiography before and after Intraretinal or Subretinal Fluid Resorption in Exudative Age-Related Macular Degeneration: A Pilot Study

The aim was to analyze the variations in macular vascularization on optical coherence tomography angiography (OCTA) according to the presence of intraretinal fluid (IRF) induced by exudative age-related macular degeneration (AMD). We included exudative AMD patients with IRF and/or subretinal fluid (SRF) and age-matched control eyes. All patients underwent a macular 6 × 6 mm swept-source OCTA. The mean perfusion density (MPD) and mean vascular density (MVD) were calculated in the superficial (SCP) and the deep (DCP) capillary plexus at two timepoints: during an episode of exudation (T0) and after its total resorption (T1). A total of 22 eyes in the IRF ± SRF group, 11 eyes in the SRF group and 11 eyes in the healthy group were analyzed. At T0, the IRF ± SRF group showed significantly lower MPD and MVD than healthy eyes in the SCP (p < 0.001) and DCP (p < 0.001). At T1, MPD and MVD significantly increased from T0 in the SCP (p = 0.027 and p = 0.0093) and DCP (p = 0.013 and p = 0.046) but remained statistically lower than in the healthy eyes. For the SRF group, only the DCP showed significantly lower MPD (p = 0.012) and MVD (p = 0.046) in comparison to the healthy eyes at T0. The present study shows that retinal vascular changes do occur in the case of exudative AMD.

Updates on the Management of Ocular Vasculopathies with VEGF Inhibitor Conbercept

Purpose: To provide a detailed review on the therapeutic efficacy of conbercept for the management of ocular vasculopathies. Methods: A comprehensive literature search of various electronic databases was performed. Results: Ocular vasculopathy is one of the major causes of visual impairment and blindness which includes a range of disorders. Vascular endothelial growth factor (VEGF) regulates angiogenesis, enhances vascular permeability, and drives the formation of neovascularization. Anti-VEGF therapy has been shown to prevent vision loss or potentially improve vision in patients with exudative or neovascular retinal disease. The most recent anti-VEGF drug in China is conbercept. In the USA and Europe, bevacizumab is the most recently approved anti-VEGF agent. Conclusions: Conbercept serves as another anti-VEGF option for patients with neovascular AMD and other retinal vascular disorders. There have not been many clinical trials that study conbercept as compared with other currently available anti-VEGF drugs. There is a need for large-scale, well-designed, randomized clinical trials to ensure its long-term safety and efficacy and to determine if it has any advantages over other anti-VEGF agents.

Evaluation of Microvascular Structure Changes after Conbercept Treatment on Macular Edema Secondary to Retinal Vein Occlusion

Aims

To confirm the therapeutic efficacy of conbercept for the treatment of macular edema (ME) secondary to retinal vein occlusion (RVO) by using optical coherence tomography angiography (OCTA) and to find out the differences in therapeutic efficacy between ischemic and nonischemic retinal vein occlusion (iRVO or non-iRVO) after conbercept treatment.

Methods

In this prospective, randomized, and comparative study, 60 unilateral eyes suffered from RVO combined with macular edema were included and fellow eye as controls. After an initial intravitreal injection of conbercept (IVIC), a pro re nata (PRN) strategy was adopted, and the follow-up time was 6 months. The foveal avascular zone (FAZ), vascular density of superficial capillary plexus (SCP), and vascular density of deep retinal capillary plexus (DCP), nonperfused areas (NPAs) were evaluated with OCTA on baseline and after treatment.

Results

The mean intravitreal injection number was 2.9 ± 0.89 times during six months in iRVO patients and 2.1 ± 0.86 times in non-iRVO patients, with statistically significant difference (p < 0.05). On baseline, central macular thickness (CMT) and FAZ were significantly thickened and enlarged compared to those of healthy fellow eyes; the vascular density of SCP and DCP were significantly decreased, and the differences were statistically significant (p < 0.05). Compared to baseline, after treatment, the best-corrected visual acuity (BCVA) was improved in either iRVO or non-iRVO (−0.601 ± 0.387, −0.241 ± 0.341 logMAR, p < 0.05). In iRVO, the improvement was more substantial than that of the non-iRVO group. FAZ in the non-iRVO group had significantly decreased compared to that in iRVO group (−0.044 ± 0.040 versus 0.014 ± 0.043 mm², p < 0.05). CMT, the vascular density of SCP, and DCP had no significant difference.

Conclusions

The changes of microvascular structure can be quantitatively evaluated by using OCTA for the patients with RVO. Conbercept had a significant effect on treatment of RVO with macular edema. A more profound effect was achieved in the iRVO group on visual improvement and FAZ reduction in the non-iRVO group after conbercept treatment.